KR100834857B1 - Piston device for controllable pitch propeller actuator - Google Patents

Abstract

A piston device for a controllable pitch propeller actuator is provided to reduce maintenance cost for tightening a loose nut by reducing deformation of a contact between a piston and a piston rod. A piston device for a controllable pitch propeller actuator includes a conical cylinder(1), a setting neck(2), a nut(3), and a piston rod(5). The setting neck is a projection of an end of the piston rod. The nut is fastening the setting neck of the piston rod and the piston. The nut is coupled with the setting neck and has a groove(14) to insert a projection(13) formed at a center of a body of the piston. The groove of the nut receives the projection of the piston for fastening the piston to the piston rod. The piston rod linearly reciprocates inside the conical cylinder and passes through an end plate(11) of a hub(7) in contact with a crank pin ring(8) to be in contact with a cross head(12).

Description

Piston device of variable pitch propeller actuator {PISTON DEVICE FOR CONTROLLABLE PITCH PROPELLER ACTUATOR}

1 is a cross-sectional view of a nut arrangement of a conventional variable pitch propeller hub.

Figure 2 is a cross-sectional view of the nut arrangement of the variable pitch propeller hub manufactured to reduce the stress generated in the contact surface of the piston and the piston rod according to the present invention.

3 is a view showing a finite component calculation result of a conventional variable pitch propeller actuator piston device without a protrusion.

4 is a view showing a finite component calculation result of a variable pitch propeller actuator piston device having a protrusion according to the present invention.

FIG. 5 is a graph showing a finite component calculation result of a variable pitch propeller actuator piston device having no protrusion on a conventional piston rod, and the zero point of the “ROD LENGTH” axis corresponds to a collar of the piston rod setting.

FIG. 6 is a graph showing finite component calculation results of a variable pitch propeller actuator piston device having no protrusion on a conventional piston bore, and the highest point of the “PISTON BORE LENGTH” axis corresponds to the surface in contact with the piston rod.

FIG. 7 is a graph showing a finite component calculation result of a variable pitch propeller actuator piston device having a protrusion on a piston rod according to the present invention, and the zero point of the “ROD LENGTH” axis corresponds to a collar of the piston rod setting.

FIG. 8 is a graph showing a finite component calculation result of a variable pitch propeller actuator piston device having a protrusion on a piston bore according to the present invention, wherein a peak of the “PISTON BORE LENGTH” axis corresponds to a surface in contact with the piston rod. .

<Description of Major Symbols in Drawing>

1: conical cylinder

2: setting neck

3: nut

4: piston

5: piston rod

6: pressure fluid

7: hub

8: crank pin ring

9: contact surface

11: end plate

12: cross head

13: protrusion

14: home

The present invention relates to an arrangement of piston rods applied to a hydraulic actuator of a variable pitch propeller.

U. S. Patent No. 3,150, 570 relates to a piston rod assembly that expands like a cylinder wall and at the same time holds firmly so that the cylinder wall can expand within its elastic limits. This is an assembly device combined with the piston structure that completely locks between the piston and the piston rod, which makes it very difficult to maintain the variable pitch propeller hub.

According to US Pat. No. 4,782,533, the piston and the piston rod are very firmly engaged with each other by an interference fit. In this case, the piston grip on the piston rod makes it very difficult to disassemble the piston and the piston rod.

According to US Pat. No. 5,213,472, the front end of the piston shaft is attached to the piston by a nut in the cylinder. In this case, a high contact pressure is generated between the contact surface edge of the piston rod and the contact surface according to the correlation between the diameter of the piston and the radius of the setting place where the piston rod is hydraulically operated, and as a result, the shape of the propeller hub is gradually deteriorated. Goes. In this case, it is necessary to continuously tighten the nut through regular maintenance. Preferably, the longer the period in which the nut is clamped, the better.

The present invention has been proposed to solve the above problems, by reducing the equivalent stress (equivalent stress) caused by the pressure fluid at the edge of the contact surface of the piston and the piston rod and at the same time by reducing the deformation at the contact surface It is an object of the present invention to provide a piston device of a variable-pitch propeller actuator that can reduce the maintenance costs required to retighten.

Other objects and advantages of the present invention will be described below, which are not limited to the matters set forth in the claims and the disclosure of the embodiments thereof, but also to the broader ranges by means and combinations within the range readily recited therefrom. Add that it will be included.

In order to achieve the above object, the present invention, a conical cylinder (1); Corresponds to the protrusion of the end of the piston rod (5) for linear reciprocating motion in the inner space of the conical cylinder (1), by combining the piston (4) and the nut (3) to the piston (4) and the nut (3) A setting neck 2 fixed to the rod 5; The setting neck 2 is coupled with the piston 4 and has a groove 14 for inserting a protrusion 13 formed in the center of the body of the piston 4 and into the groove 14. A nut 3 for fitting the protrusion 13 of 4) to fix the piston 4 to the piston rod 5; And a piston rod 5 which linearly reciprocates in the inner space of the conical cylinder 1 and penetrates through the end plate 11 of the hub 7 in contact with the crank pin ring 8 to be in contact with the cross head 12. It proposes a piston device of a variable pitch propeller actuator comprising a).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the following will describe a preferred embodiment of the present invention, but the technical idea of the present invention is not limited thereto and may be variously modified and modified by those skilled in the art.

1 is a cross-sectional view of a nut arrangement of a conventional variable pitch propeller hub. Variable pitch propeller hubs have a conical cylinder (1), a setting neck (2), a nut (3) for holding the piston (4) under pressure fluid (6), and an end plate of the hub (7) in contact with the crank pin ring (8) And a piston rod 5 penetrating the 11 to be in contact with the cross head 12. The piston 4 and the piston rod 5 are connected at the contact surface 9. According to FIG. 1, the nut 3 fixes the piston 4 on the contact surface 9, the piston 4 bends the circumferential surface of the body by the action force of the pressure fluid 6, and the piston 4 ) And a high equivalent stress is generated at the edge of the contact surface 9 of the piston rod 5.

Figure 2 is a cross-sectional view of the nut arrangement of the variable pitch propeller hub manufactured to reduce the stress generated in the contact surface of the piston and the piston rod according to the present invention. The variable pitch propeller hub 7 according to the invention is in contact with a conical cylinder 1, a setting neck 2, a nut 3 holding the piston 4 under pressure fluid 6, a crank pin ring 8. It comprises a piston rod (5) which penetrates the end plate (11) of the hub (7) in contact with the cross head (12). The piston 4 and the piston rod 5 are connected at the contact surface 9. The nut 3 reduces the circumferential displacement of the edge of the protrusion 13 by tightly fitting the protrusion 13 formed in the center of the body of the piston 4 into the groove 14 formed in the center of the body.

According to FIG. 2, the nut 3 fixes the piston 4 on the contact surface 9, which causes the circumferential surface of the body to bend by the action force of the pressure fluid 6. However, part of the load generated by the pressure fluid 6 flows from the piston 4 toward the groove 14 formed in the center of the nut 3 through the protrusion 13 formed in the center of the body of the piston 4. At the edge of the contact surface 9 of the piston 4 and the piston rod 5 a relatively low equivalent stress occurs.

That is, the pressure fluid 6 pushes the piston 4 and passes through the end plate 11 of the hub 7 to reach the cross head 12 while rotating in the hub 7. Under the influence of this pressure fluid 6 the piston 4 is subjected to a bending moment and deformation in the circumferential direction occurs. As a result, an equivalent stress occurs at the edge of the contact surface 9 of the piston 4 and the piston rod 5. At this time, the piston 4 is a part of the bending moment is dispersed toward the nut 3 because the protrusion 13 formed in the center of the body is fitted into the groove 14 of the nut 3, as a result of the conventional contact surface ( Equivalent stress, which is very high in 9), is considerably reduced in the present invention. In this case the flow in the opposite direction of the pressure fluid 6 appearing on the surfaces of the piston 4 and the nut 3 is also not so bad, because the axial length of the piston 4 according to the invention has a groove ( 14) longer than when coupled by a nut without a nut and a piston without a protrusion 13.

3 and 4 show finite component calculations of the variable pitch propeller actuator piston device without protrusions and the variable pitch propeller actuator piston device with protrusions, respectively, with a piston diameter of 0.5 m and a pressure of 5.5 MPa. The figure which showed the result. The maximum value of equivalent stress that occurs when the piston 4 with the protrusion 13 is fitted to the nut 3 with the groove 14 is that the piston 4 without the protrusion 13 About 13.6% was reduced compared to the case where the nut 3 without the groove 14 is fitted. This reduction in equivalent stress also reduces deformation at the contact surface 9, which results in significantly reduced maintenance costs by increasing the time interval of maintenance required to retighten the loosened nut.

5 and 7, the maximum value of equivalent stress generated in the case of the present invention (FIG. 7) is much smaller than the maximum value of equivalent stress generated in the conventional case (FIG. 5). It can be seen. This is also the case when comparing FIG. 6 with FIG.

The above descriptions are merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. It will be possible. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, according to the present invention, the equivalent stress caused by the pressure fluid at the contact surface edge of the piston and the piston rod is reduced and also the deformation at the contact surface is reduced, so that in order to finally tighten the loosened nut The maintenance cost required can be reduced.

Other effects of the present invention, as well as those described in the above-described embodiments and claims of the present invention, as well as potential effects that may occur within the range that can be easily estimated therefrom and potential advantages that contribute to industrial development It will be added that it will be covered by a wider scope.

Claims (1)

Conical cylinder 1; Corresponds to the projection of the end of the piston rod (5) in a linear reciprocating motion in the inner space of the conical cylinder (1), by combining the piston (4) and the nut (3) to the piston (4) and nut (3) A setting neck 2 fixed to the rod 5; The setting neck 2 is coupled with the piston 4 and has a groove 14 for inserting a protrusion 13 formed in the center of the body of the piston 4 and into the groove 14. A nut 3 for fitting the protrusion 13 of 4) to fix the piston 4 to the piston rod 5; And Piston rod (5) which makes a linear reciprocating motion in the inner space of the conical cylinder (1) and penetrates the end plate (11) of the hub (7) in contact with the crank pin ring (8) to contact the cross head (12). Piston device of a variable pitch propeller actuator comprising a.

Images